import Vue from 'vue';

/*

*  使用方法

*  将以下代码复制到一个js文件中，然后在入口文件main.js中import引入即可；

*  给elementUI的dialog上加上 v-dialogDrag 指令就可以实现弹窗的全屏和拉伸了。

*  给dialog设置 :close-on-click-modal="false" , 禁止点击遮罩层关闭弹出层

*  如果是form表单，不要将提交等按钮放置el-form-item，以免在上下拉伸时被隐藏

*/

// v-dialogDrag: 弹窗拖拽+水平方向伸缩

Vue.directive('dialogDrag', {
  //bind 只执行一次 update被绑定组件更新时就调用
  update(el, binding, vnode, oldVnode) {

      //弹框可拉伸最小宽高

      let minWidth = 400;

      let minHeight = 300;

      //初始非全屏

      let isFullScreen = false;

      //当前宽高

      let nowWidth = 0;

      let nowHight = 0;

      //当前顶部高度

      let nowMarginTop = 0;

      //获取弹框头部（这部分可双击全屏）

      const dialogHeaderEl = el.querySelector('.el-dialog__header');

      //弹窗

      const dragDom = el.querySelector('.el-dialog');

      //给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；

      dragDom.style.overflow = "auto";

      //清除选择头部文字效果

      //dialogHeaderEl.onselectstart = new Function("return false");

      //头部加上可拖动cursor

      dialogHeaderEl.style.cursor = 'move';

      // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);

      const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

      let moveDown = (e) => {

          // 鼠标按下，计算当前元素距离可视区的距离

          const disX = e.clientX - dialogHeaderEl.offsetLeft;

          const disY = e.clientY - dialogHeaderEl.offsetTop;

          // 获取到的值带px 正则匹配替换

          let styL, styT;

          // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px

          if (sty.left.includes('%')) {

              styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);

              styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);

          } else {

              styL = +sty.left.replace(/\px/g, '');

              styT = +sty.top.replace(/\px/g, '');

          };

          document.onmousemove = function (e) {

              // 通过事件委托，计算移动的距离

              const l = e.clientX - disX;

              const t = e.clientY - disY;

              // 移动当前元素 

              dragDom.style.left = `${l + styL}px`;

              dragDom.style.top = `${t + styT}px`;

              //将此时的位置传出去

              //binding.value({x:e.pageX,y:e.pageY})

          };

          document.onmouseup = function (e) {

              document.onmousemove = null;

              document.onmouseup = null;

          };

      }

      dialogHeaderEl.onmousedown = moveDown;

      //双击头部全屏效果

      dialogHeaderEl.ondblclick = (e) => {

          if (isFullScreen == false) {

              nowHight = dragDom.clientHeight;

              nowWidth = dragDom.clientWidth;

              nowMarginTop = dragDom.style.marginTop;

              dragDom.style.left = 0;

              dragDom.style.top = 0;

              dragDom.style.height = "100VH";

              dragDom.style.width = "100VW";

              dragDom.style.marginTop = 0;

              isFullScreen = true;

              dialogHeaderEl.style.cursor = 'initial';

              dialogHeaderEl.onmousedown = null;

          } else {

              dragDom.style.height = "auto";

              dragDom.style.width = nowWidth + 'px';

              dragDom.style.marginTop = nowMarginTop;

              isFullScreen = false;

              dialogHeaderEl.style.cursor = 'move';

              dialogHeaderEl.onmousedown = moveDown;

          }

      }

      dragDom.onmousemove = function (e) {

          let moveE = e;

          if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 || dragDom.offsetLeft + 10 > e.clientX) {

              dragDom.style.cursor = 'w-resize';

          } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {

              dragDom.style.cursor = 's-resize';

          } else {

              dragDom.style.cursor = 'default';

              dragDom.onmousedown = null;

          }

          dragDom.onmousedown = (e) => {

              const clientX = e.clientX;

              const clientY = e.clientY;

              let elW = dragDom.clientWidth;

              let elH = dragDom.clientHeight;

              let EloffsetLeft = dragDom.offsetLeft;

              let EloffsetTop = dragDom.offsetTop;

              dragDom.style.userSelect = 'none';

              let ELscrollTop = el.scrollTop;

              //判断点击的位置是不是为头部

              if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {

                  //如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;

              }else{

                  document.onmousemove = function (e) {

                      e.preventDefault(); // 移动时禁用默认事件

                      //左侧鼠标拖拽位置

                      if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {

                          //往左拖拽

                          if (clientX > e.clientX) {

                              dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px';

                          }

                          //往右拖拽

                          if (clientX < e.clientX) {

                              if(dragDom.clientWidth < minWidth){

                              }else{

                                  dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px';

                              }

                          }

                      }

                      //右侧鼠标拖拽位置

                      if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {

                          //往左拖拽

                          if (clientX > e.clientX) {

                              if (dragDom.clientWidth < minWidth) {

                              } else {

                                  dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px';

                              }

                          }

                          //往右拖拽

                          if (clientX < e.clientX) {

                              dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px';

                          }

                      }

                      //底部鼠标拖拽位置

                      if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {

                          //往上拖拽

                          if (clientY > e.clientY) {

                              if (dragDom.clientHeight < minHeight) {

                              } else {

                                  dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px';

                              }

                          }

                          //往下拖拽

                          if (clientY < e.clientY) {

                              dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px';

                          }

                      }

                  };

                  //拉伸结束

                  document.onmouseup = function (e) {

                      document.onmousemove = null;

                      document.onmouseup = null;

                  };

              }

          }

      }

  }

})